Vehicle seats, such as aircraft seats, typically include a frame defining seat back and bottom portions for supporting the seat occupant. To provide comfort to the seat occupant, at least the back and bottom portions are typically covered with some type of resilient cushioning material, such as foam and like materials. To protect the foam against wear and damage, the cushioning material is typically covered with a robust fabric that moves with and contours to the shape of the foam. The fabric covering may also function to maintain the cushioning material in place and may be patterned or colored to provide decoration to the seat.
For safety and fire prevention, it is not uncommon for the fabric covering to be made from or treated with a flame-retardant material in order to decrease the flammability of the covering and the cushioning material beneath it. However, conventionally treated fabrics are not able to adequately insulate the underlying cushioning materials from radiant heat flux resulting from a fire within the passenger compartment. As a result, cushioning materials exposed to sufficient heat flux can cause the materials to ignite and/or release smoke and fumes. The contribution of heat, flame and smoke density to the cabin atmosphere from additional burning materials increases the rate at which the fire spreads and decreases the time in which passengers have to escape.
Federal Air regulation 25.853(d) details testing requirements for determining the acceptability of materials utilized in aircraft interiors. Regulation 25.853(d) includes two separate tests: (1) the OSU Rate of Heat Release Test, and; (2) the Smoke Density Test. The OSU Rate of Heat Release Test involves exposing aircraft interior cabin materials to incident radiation heat flux, and measuring the rate at which a burning item releases heat. The OSU test can be used to determine at what temperature certain interior materials will ignite, thus starting a fire or contributing to the spreading of an existing fire. The second test, the Smoke Density Test, is used to measure and observe the relative amounts or density of smoke produced when a material is burned. This test is also useful in determining the smoke contribution of a burning material to the aircraft cabin atmosphere and the decrease in visibility that occupants will encounter in exiting the passenger compartment during a fire.
Conventional materials often have difficulty in meeting the requirements of these tests. Generally, foams and other flammable materials used in cushions and protective pads on aircraft seats and other furniture and partitions do not perform well in one or both of these tests unless the material itself has been treated with or constructed from flame retardant additives.
Accordingly, it would be desirable to provide an insulating layer between a flammable material and high temperatures in a passenger compartment, thus protecting the material and decreasing its hazard potential. Further, it would be desirable to provide a layered insulating cover for flammable cushioning materials to shield the materials from heat flux that could cause the materials to ignite and/or contribute smoke to the cabin environment. A desirable insulating cover would be flexible so as not to reduce the comfort of the cushioning material, and would obviate the need to treat or construct the cushioning material using flame-retardant additives or materials.